Please, observe MethodHandles.iteratedLoop(...) constraints for iterator, init and body.

According to these constraints, three MethodHandle with following signatures should be accepted in abovementioned method :
iterator=()Iterator
init=()I
body=(I,Object,I)I

Let's look on their types. First I is locals state, Object is T, and second I is single loop argument. Init's parameter list should be effectively identical to loop parameter list (it is 'I'). The same requirements for iterator handle. However, following exception occurs:
>> Exception in thread "main" java.lang.IllegalArgumentException: inferred first loop argument must be an array or inherit from Iterable: int

Observing last constraint you can find constraint (first argument must be Iterable or array) in the case iterator=null. Here iterator is not null, so it is inapplicable.
You can find complete code in Example0.java


Was found on jdk9b140